This invention relates to a lock for a movable wing, and particularly to a lock intended to be rim fitted to a domestic entrance door.
An object of the invention is to provide such a lock in an improved form.
According to the invention a lock for a wing movable between respective open and closed positions relative to a frame comprises a casing, a bolt operable to extend from or to retract into said casing, an operating member arranged to be operable at one side of the wing, in use, from a rest position to an operated position normally to effect retraction of said bolt, the casing having an interior portion with an aperture therethrough to receive fixing means for securing said casing to said wing, in use, access for an implement to fasten or release said fixing means being through an opening in said casing, which opening is blocked by said operating member, thereby to prevent such access, when said operating member is in its rest position.
Preferably the operating member is biased to its rest position. Desirably said operating member has a cutout in part thereof so that when said operating member is in its operated position, part of said implement can be received through the cut-out to access said fixing means. Conveniently the operating member is lockable in its rest position to prevent such access. Advantageously said fixing means extend, in use, through a cover which closes an open side of the casing and is itself, in use, secured to said wing. Most preferably the fixing means is a screw engaged in a tapped hole in said cover.